ROXANE Gilbert had one question as she lay on the lounge room floor bleeding to death - why?
Her chilling last words came out in court as a police interview with Horace Lorenzo Jones was played for the jury on day three of his trial.
Jones, 21, has pleaded not guilty to murdering his mother, who lived in Bundaberg, with a samurai sword and steak knife in his Gladstone home on June 29, 2012.
Ms Gilbert's body was found wrapped in a plastic drop sheet and tarp in the back seat of her abandoned car near the Calliope River the next day.
She had 31 cuts and stab wounds.
During the video, the Rockhampton Supreme Court yesterday heard Jones tell police he "had some built up fury".
Jones said the night before Ms Gilbert's death he heard her hitting his three-year-old brother.
"It made me feel so angry," he said. "I just had a feeling it could happen at any time... if she went too far it could happen."
He said that morning he "just snapped".
In gruesome detail, Jones explained to detectives how he used an ornamental sword to "pierce her heart".
"It pretty much deflated... it did deflate," he said. "It's the sorriest thing I had to do."
Jones said his mother kept asking: "Why are you doing this? I'm your mum".
"You treat me like I'm no one, I'm not your son," he said he replied.
Jones told police he knew what he did was wrong.
"If I could I would take it back, but what I've done is permanent," he said.
According to Jones, the pair had a "dark" relationship.
The trial continues today.